Dairy farmers feed calves colostrum, transitional milk, milk and/or formula for the first six to twelve weeks of a calf's life. Throughout this article, "milk" will refer to all milk except formula. Cow's milk has economic value and therefore, farmers that feed milk typically use milk that does not meet the quality requirement for human consumption. This milk is referred to as "non-saleable" or waste milk. Waste milk does not meet the quality standards because it comes from a cow that either has a disease or is being treated with antibiotics to rid the cow of a disease. On average, 2% of a dairy herd carries a disease that make the milk produced by the diseased cows non-saleable. Pasteurization is one method of improving the quality of waste milk by reducing the potential for disease transmission to the calf.
Formula is used as a food source for calves because it is free from disease, easy to prepare and costs less to feed than saleable milk. Unfortunately, it is still expensive and does not provide the same level of nutrition as cow's milk.
A pregnant cow will not give milk for the last 45-60 days of pregnancy. The first milk produced by the cow after giving birth is colostrum. Colostrum contains antibodies and other important nutritional components critical for the newborn calf. The next couple of milkings after colostrum are referred to as transitional milk. Transitional milk has fewer antibodies and less fat than colostrum.
University research indicates that if colostrum is pasteurized before it is fed to the calf, the calf will weigh more and therefore, is worth more when it goes to market. The antibodies and proteins in colostrum and transitional milk are very sensitive to heat. Colostrum can be pasteurized but the temperature and heating duration must be controlled to limit the damage to proteins and antibodies. The temperature and time that has been demonstrated to be most effective is 161.degree. F. for 15 seconds.
This temperature and time relationship is common in the pasteurizing industry and is referred to as High Temperature Short Time (HTST) pasteurization. Nearly all pasteurized milk consumed by humans today is pasteurized using HTST.
Onsite pasteurization has not been economically feasible up to now because of the complexity and therefore, cost of pasteurizing systems. Pasteurizing systems that were originally designed for pasteurizing products other than cow's milk are being sold to dairy farmers as pasteurizers for milk destined for calves. These pasteurizers are very expensive and have not been designed with the dairy farmer in mind.
Dairy farmers are very busy. A pasteurizer built for today's dairy farmer needs to perform quickly, be easy-to-use, cost effective and require low maintenance. Other systems use water heat or large metal plates for heat exchange. These systems heat up slowly, and therefore, increase the amount of time required to process a batch of milk. Other systems also require multiple operator steps and depend on additional accessories, like tanks, for effective operation.
Consequently, an affordable, convenient way to pasteurize the milk that dairy farmers feed their calves is needed. Such a pasteurizer can give the dairy farmer a means for significant economic benefit through decreased dependence on formula and increased calf health and market value.